Bond-tester.



J. B. WEST.

BOND TESTER.

APPLICATION FILED IEB. 1, 1906.

Patented May 3, 1910.

2 SHEETS-SHEET 1.

J. B; WEST.

BOND TESTER.

APPLICATION rnnn FEB. 1. 1906.

2 SHBSTB-BBBBT 3.

Patented May 3, 19 10.-

M'Zrwsses- JOHN B. WEST, OF SYRACUSE, NEW YORK.

BOND-TESTER.

Specification of Letters Patent.

. Patented May 3, 1910.

Application filed February 1, 1906. Serial No. 298,988.

To all wlwm it may co ncem:

Be it known that I, JOHN B. Wns'r, of Syracuse, in the county of Onondaga, in the State of New York, have invented new and useful Improvements in Bond-Testers, of which the following, taken in connection with the accompanying drawings, is a full, clear, and exact description.

This invention relates to certain improvements in bond-testers for testing the bonds and joints of electric railways for the purpose of locating loose bond connections or breaks in the continuity of the electric conductors. It is well known that it is quite impossible to permanently secure these bonds to the rails, and that they are continually loosening or breaking at different points along the line of railway, thereby materially interfering with the perfect operation of the said railway'and producing greater or less loss of power. It is also well known that however wellthe bond may be secured to the rails, the resistance at the 'oints always exceeds the normal resistance of my invention is particularly ada ted to make a comparative test between t e electrical resistance of the erfect rail and the joint or meeting ends 0 two adjacent rails soas to determine .whether or not the electrical connection at such joint is up to the standard degree of conductivity of the bondconnection.

Another object of my invention is to produce a comparatively light portable tester which may be carried in the hand from place to place, and contains within a comparatively small space, all the requisite elements for makinga comparative test of the resistance of the joint or bond with that of the rail proper, the one device constituting a unitary structure having a tubular handle of small diameter containing all of the elements necessary for the test with the single exception of the receiver which is small and can becarried in the pocket to be attached during the testing operation.

A further object is to equip the device with automatic prick punches which under pressure by the operator, are caused to penetrate any superficial material encountered thereby in making a test so as to obtain more perfect electrical contact with the meeting ends of the rails.

In the drawings'Fi ure 1 is an elevation, partly broken away, 0 my improved bondthe rail, and

. are passe tester. Fig. 2 is an enlarged longitudinal sectional view, partly broken away, .of the upper portion of the handle-tube seen in Fig. 1, showing the upper ends of the primary and secondary coils. Fig. 3 is a similar sectional view of an additional portion of the tubular handle, partly broken away, but in which the rimary and secondary coils and make and break contact switch are mounted, the central portion of the primary and secondary coils being broken away. Fig. 4 is an enlarged transverse sectional view, taken on line 4:-4, Fi 1. Fig. 5 is a side elevation, partly bro en away of a receiver having an adjustable diaphragm. Fig. 6 is a transverse sectional view through the receiver seen in Fig. 5. Fig. 7 is an elevation of the lower end of the bond-tester shown as applied to the meeting ends of adjacent rails formin parts of an electric; circuit. Fig. 8 is a sectional view of one of the prick unches.

In carrying out tli vide a tubular metal handle -l with a suitable foot or oppositely projecting arms -2- in the outer ends of which are located automatic prick punches 3- having spurs or points -4 which are electrically connected by wires -5 to the ends of a primary coil 6- within the tubular handle --.1. The wires 5 are flexibly and electricall connected to the spurs 4 and upwardly from the bottom into the tubular handle 1 where one of them is permanently and electrically connected by a conductor -5' to one end of a primary coil while the other wire is connected to a switch or make-and-break contact device 7-, one of the terminals of the switch being electrically connected to the other end 'of the rimary coil -.6. as best seen in Fig. 3. T is primary coil 6- consists of a suitable number of windings or turns of the desired axial length upon a tube 8 of insulating material such as fiber or stilt paper, having its base as.8-- enlarged to fit snugly within the interior of the tube l where it is secured or held in fixed relation to the outer tube by suitable fastening means as screws --9-. A.

ortion of the base --8- of the tube -8-- is cut away for receivin and permitting the o eration of the movable member as 7- o the switch -7'.-., said movable member having a push-button or finger piece 10-- e objectsstated, I pro-" mary circuit may be more frequently in- I, "opening 11- in the outer metal tubular secured thereto and projecting through an handle finger. I

' he movable switch member 7 consists in this instance of a spring finger or l, where it is accessible by the conductor which is spring-pressed tonoris a secondary tube -15- o broken away in Fig. 3.

mally close the switch 7', the latter being op ned by inward pressure upon the pushbu ton --10 to break the circuit through the primary coil 6- when desired.

I preferably provide an' extra contact member 12 for the movable member 7, such member being also in electrical connection with the same end of the primary coil as the switch --7 through the medium of connecting bonds 13 and forms a stop for the movable member 7 and establishes an additional make and-break contact for said member whereby the priterrupted to increase the number of times that the electro-motive force will rise to a certain value in the secondary circuit and thereby increasing the efliciency of the device; it being noted that the contacts 7 and. 12 are sufficiently spaced apart to prevent an accidental short circuiting therebetween.

The electric conductors 5 and 5"- and also the elements of the switch -7' are supported in the insulating base 8'- of the fiber tube 8 in such manner as to prevent electrical connection of said parts with the outer metal tube '1. The up er end of this insulatin tube 8 is provi ed with an enlarged. ead 14- which is also snugly fitted within and secured to the metal tube -1-, thereby rigidly holding theprimary coil 6 in a fixed positionin the tubular handle -1. 1

- Movable within the insulatin tube -8.

fiber, stifi paper or equivalent material of somewhat greater length than the axial length of the primary e011 --6--' so as to extend beyond the opposite ends of the latter and a considerable distance below its lower end to guide the tube 15- in its longitudinal movement. This inner tube .-15 is secured at its ililpper end to an enlar d head 16* of ins atingmaterial as figgr which is fitted with an easy sliding fit within the tubular handle 1- and to this head is secured by wound thereon "a secondary 1 and down by means of a ary coil 20- is electrically connected to the lower end of the core 19- and. its other end is electrically connected to a metal conductor 22 extending throu h .the up er insulating head 16- of the sllding tu e --15-.

The core 19-- and its secondary coil 20 are fixed within the insulating tube ,15-- to move endwise or axially therewith. A suflicient space is left in the up er end of the outer casing or tubular hand e 1- to permit the secondary coil 20- and its core l9- to be drawn upwardly from a position within the primary coil 6 to a position entirely above the latter coilv so that the inductive effect of the primary upon the secondary coil may be gradually varied 'from a maximum to a minimum degree. I A pair of parallel guide-rods 25, are arhave their lower ends screwed or otherwise secured in the insulating head l tand their upper ends are similarly secured in a cap 26 of insulating material vin the upper end of the tubular handle 1 and are electrically connected by conductors 27- to suitable binding posts 28-- on the insulating cap 26--.

I' have reviously stated that one end of the secon ary coil 20-- is electrically connected to the core ,-19 which is in elec trical contact with the metal disk 18 and through the medium of the screw 17 which enga es with said-'metal disk 18 is electrical y connected to a brush 29' on the upper surface of the sliding insulating head -'16'-, the other end of said secondary coil being electrically connected byawlre 22- to a second contact brush 29' also mounted upon the u per end of the insulating head --16. T ese brushes 29 and 29'-- are in sliding electrical contact with the parallel guiderods 25-, and, therefore, the secondary coil 20- is electrically connected through the medium of the brushes 29- and '-29 and metal guide-rods or conductors 4 25- to the binding posts 28--.

A suitable telephone-receiver 30- or equivalent visual or audible indicator is connected by wires 31- to the binding posts 28-, thereby establishing electrical connection between the receiver and secondary-coil 20.

-20, together with its core 19-- and tube 15- is moved longitudinally, or up and:piece 32-- having one end inserted in an aperture 33+. in the head 16- and its other end passed outward] through .a slot 34- in the tubular han le --1 and provided with a suitable hand-knob 35 and an index finger --36, which latter is arranged to ranged within the tubular handle -1 and 4 v The head 16.-' and secondary-coil joints of adjacent rails, the foot 0 a travel along an index or series of graduations -37- on the tube --1- as the secondary coil is moved longitudinally.

The inner end of the socket -33- in the head 16- is enlarged to receive a retracting spring -38 and a nut 39- against which the spring 38 abuts and operates to force the plunger 32- inwardly or axially so as to frictionally engage the head of the plunger or index fingers 36- with the outer face of the tube to hold the secondary coil and parts moved therewith in their adjusted position with reference to the outer tubular casing or handle -1, the nut -'39 being ad ustable to vary the tension of the spring -38--- for the purpose of increasing the friction between the head of the plunger and outer tube when desired.

The scale 37. is calibrated approximately to a known resistance. as for instance, the known resistance 'of a standard rail, which in this instance corresponds to a reading slightly above zero so as to allow for slight variations in the rail resistance, according to varying densities of different parts of the rail.

' In testing the electrical leakage or resistance of the joints or bonds connectin the f the handle -1 is made to span such joint so that one of the spurs 4- rests upon the adjacent end of each of the rails, whereupon the device is pressed downwardly with sufficient force to operate the prick punch -3- to cause the spurs 4-- to penetrate any ordinary scale or dirt which may be on the surface of the rail, thereby establishing a more perfect electrical connection between the spurs and rails. If there is no leaka e of the current at the joint, such as won (1 be produced by a broken or loose bond, there would be very little if any current'flowing in the primary coil --6, and therefore, the induced current in the secondary coil would be insuflicient to produce any audible sound in the receiver, it being understood that by making and breaking the primary circuit through the medium of the switch 7 and contact member -12 the electromotive force of any slight currentwhich might flow inthe primary circuit would be magnified in the secondary circuit, the effect being similar to that. produced by the ordinary vibratorof a spark coil. On the other hand, if the bond was broken, or the continuity of the circuit was incomplete through the rail there would be a leakage of the current through the primary coil which would be induced into the secondary coil and cause more or less audible disturbance ,in the receiver -3,0-, which of course, is held to the ear while the test is being made. If this audible disturbance in the receiver is sharp and well i defined, it indicates that the break at the joint or bond is excessive and by withdrawb the receiver, the comparative degree of e ectrical resistance may be accuratel determined b the location of the index ger -36- witli reference to the graduations on the scale -37.' For example, if the adjustment of the secondary coll necessary to brin the audible disturbance to a. minimum is slight it indicates thatthe bond or electrical connection at the "oints is only slightly imperfect, whereas if t e adjustment is excessive it indicates a correspondingly excessive break in the continuity of the circuit at the joint.

In Figs. 5 and 6 I have shown a receiver -"30 as provided with an adjustable cap 40 in which is seated the usual diaphragm 41, the latter being locked in the cap l0-- by a screw threaded ring 42, best seen in Fig. 6 so that by rotating the cap in one direction or the other it is moved endwise and carries with it the diaphragm --t1 toward and from the electromagnets, as -43. This principle of adjusting the diaphragm relatively to the magnets may also be used independent-1y of the adjustment of the secondary coil ,-20 to test excessive leakages or imperfect electrical connections at the joints of the rails or bonds bridging such rails. For example, the action of the diaphragm will obviously be more sensitive to slight leakages at the joints when close to the magnets, and by unscrewing the cap 40 so as to gradually draw the diaphragm away from the poles of the magnet this sensitiveness gradually decreases, and if the current leakage is excessive the diaphragm may be drawn outwardly hy'unscrewing the cap until the electrical effect, or audible disturbance of the magnets upon the diaphragm is lost. I have, therefore, calibrated the rotary part or cap of the receiver and its base to indicate the comparative conductivity of the standard rail with varying degrees of leakage at the joints or bonds, taking the most perfect electrical connection of a bond as a standard or zero when the diaphragm is normally close to the pole-pieces of the magnet.

As seen in Fig. 5, the base as 44- of within the primary coil-.-'6 because the receiver is connecteddirectly to the second- 'the ear, the degr ary' coil and'derives current therefrom. If this leakage is sufiicient to produce a disturbance of the diaphragm -41 the cap -40? maybe rotated or unscrewed thereby.

movin the diaphragm away from the po e pieces of the magnet until the audi- 1 ble disturbance. of the diaphragm is lost or of leakage as compared with the normal coni of the bond connection and env ductivity ables the operator to determine whether it is advisable to readjust or connect so as to produce a better electrical connection between the rails. This adjustment, of the diaphragm with-reference to the pole-pieces of the magnet serves substantially the same purpose as the adjustment of the secondarycoil -20. with reference to its primary coil -6 and enables the operator to make the test either by adjustment of the coil 20, or by adjustment of the diaphragm 1 ,41- of the receiver, the latter being suflicient for ordinary work, while the former, or adjustment of the coil, enables the detection of comparatively slight leakages or imperfect bonds.

In Fig. 7 I have shown my improved bond tester as applied to the meeting ends of rails --a connected b a bond (1, said rails being shown in an e ectric circuit wwith a dynamo -d,' the latter being shown diagrammatically in said Fig. 7..

In the sectional view of the prickpunch' shown in Fig. 8 itgwill be noted that the spur 4 is held within the tapering holder which is screw-threaded within the lower end of the main ,casing 51 of the punch, whlch casing is in turn screw-threaded withm an aperture positionedadjacent the free end of the foot orarm 2. Said spur is provided with an encircling helical spring 52 provided within the chamber 53 of said an insulated extension provided on the bot-' holder which cushions said spur. The main casing 51 being tubular and having the usual block54, spring 55 and the other usual ele-. ment found in suchdevice positioned therein. Having thus described my invention, what I claim: j 1. In a device of the class described, atubular handle provided with. projecting feet, cpntact terminals secured to the free ends of said feet, a tube of insulating ma terial, a primer coil wound upon sai tube and closely fitting within said handle, and securing means for fixedl posltlon ng the same therein, said coil being Pos tioned in spaced relation from the top 0 said handle,

tom of said coil, conductors extending through said extension, and electrical conthe bond 3. In a device of the class described, a

. terial, a primary p beaten nectors between said conductors and said contact terminals, means for making and breakin the circuit between the primary coil and sai terminals, a secondary coil slidable longitudinally within the primary coil, rod conductors, said secondary coil provided with spring terminals in contact with the rod conductors, binding posts positioned on the top of said handle, conductors between said rods and binding posts, means for communicatin the degree of adjustmentpf the sliding C01 and a receiver in electrical connection between saidbinding posts.

2. In a device of the. class described, a tubular handle provided with projecting feet, contact terminals secured to the free 'ends of said feet, a tube of insulatin material, a primar coil wound upon sai tube and closely. fitting within said handle, and securing means for fixedly positioning the same therein, said coil being positioned in spaced relation from the top of said handle,

an insulated extension provided on the bot, tom of said coil, conductors extending through said extension, and electrical con-i nectors between said conductors and said contact terminals, said extension provided, with a cut away portion at one side thereof,

a resiliently -mounted make and break switch positioned in said cut away portion and in circuit between the primary coil and one of saidcontact terminals, a secondary coil slidable longitudinally within the primary coil, and a receiver in circuit with the secondary coil. 10o

tubular handle provided vwith projecting feet, contact terminals secured to the free ends of said feet, a tube of insulating macoil wound u on said tube 5 and closely fitting withinsai handle, and securin means for fixedly positioning the same t erein, said coil belng ositioned in spaced relation from the top 0 said handle,

an insulated extension provided on the bot,- 11.0 tom of said 0 coil, conductors extending through said extension, and electrical con- ,nectOrs-between said conductors and said contact terminals, said extension provided with a cut away portion at one side thereof,

a resiliently-mounted make andbreak switch positioned in said cut away portion and in circuit between the primary coil and one of sald contact terminal -a seconda coil slidable longitudinally wlthin the pn- 12o ma'ry coll, said secondary coil rovided with a core and one terminal of said coil in con: tact therewith, two spring contacts positioned upon the upper end of the secondary 0011, one of said contacts in circuit with said core and the other contact connected with the other terminal of'said coil, rods positionedinteriorly and longitudinally of said handle and oppositel -arranged,.sa1d spmng contacts having slid ble. connections w1th'1139' said rods, anda receiver in circuitwith said rod.

4. In a device of the class described, a tubular handle provided with projecting feet, contact terminals secured to the free ends of said feet, a tube of insulatin material, a primary coil wound u on sai tube and closely fitting within sai handle, and securing means for fixedly positioning the same therein, said coil being ositioned in spaced relation from the top of said handle, an insulated extension provided on the bottom of said coil, conductors extending through said extension, and electrical connectors between said conductors and said contact terminals, said extension provided with a cut away portion at one side thereof, a resiliently-mounted make and break switch posit oned in said cut away portion and in circuit between the primary coil and one ofi-said contact terminals, a secondary coil slidable longitudinally within the primary coil, said secondary coil provided with a core and one terminal of said coil in contact therewith, two spring contacts posiprovided upon said hand piece and graduations provided upon said handle adjacent said slot.

In witness whereof I have hereunto set my hand this 17th day of January 1906.

' JOHN B. WEST.

Witnesses: i

H. E.- CHASE, Mmmnn M. Notl'r. 

